Compressor lubrication system

ABSTRACT

A rotary compressor having improved means for removing gasses from the lubricating oil to prevent scoring and galling of the rotor bearings. The gas-removing means separates the bulk of any gas carried in the lubricating oil prior to the delivery thereof to the bearings. A supplemental gas-removing means is provided for removing further gas developed in the oil by vaporization of the gas-forming liquid in the oil as an incident of heating thereof by the relatively high temperature bearings.

O United States Patent 1191 1111 3,804,202 Funke Apr. 16, 1974 [541 COMPRESSOR LUBRICATION SYSTEM 3,692,435 9/1972 lida et a1 l84/6.l8 x Inventor: Ludwig F. Funke, Evansville Ind. 3,674,382 7/1972 Kubota et a1. 417/372 [73] Assignee: Whirlpool Corporation, Benton Primary Examiner-Manuel A. Antonakas Harbor, Mich. Attorney, Agent, or Firm-Hofgren, Wegner, Allen, 22 Filed: Aug. 2, 1972 Stenma & Mccmd [21] Appl. No.: 277,323 [57] ABSTRACT A rotary compressor having improved means for re- 52 us. c1 184/6.16, 184/618, 417/372 moving gasses from the lubricating Oil to prevent scor- 51 1m. (:1. F04b 17/00, FO4b 39/02, FOlm 1/00 s and gallihg 9f the rotor bearmgs The g [58] Field of Search 184/616, 6.18, 6.23; removing means Separates the bulk of any s carried 417/372, 418/91, 97, 99 in the lubricating oil prior to the delivery thereof to the bearings. A supplemental gas-removing means is 5 References Cited provided for removing further gas developed in the oil UNITED STATES PATENTS by vaporization of the gas-forming liquid in the oil as 2 738 919 3/1956 R h t 1 417/372 an incident of heating thereof by the relatively high use 1: a. 3,285,504 11/1966 Smith 1. 417/372 temperature bearmgs' 3,182,901 5/1965 Solomon 417/372 10 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to compressors and in particular to rotary compressors having means for circulating oil to the bearings thereof.

2. Description of the Prior Art In one form of compressor for use in compressingrefrigerant fluid in a refrigeration system, the refrigerant is compressed by a rotor carried on a shaft rotatably journalled in suitable bearings. The rotor bearings are lubricated by a pumping system which draws the collected oil from a sump and urges it between the shaft and bearings in a recirculating manner.

In'sucha system, the lubricating oil tendsto pick up refrigerant fluid. Such fluid, when vaporized by contact of the oil with the relatively hot bearings, tends to vaporize thereby causing gas lock preventing proper lubrication of the bearings and resulting in galling and scoring of the bearing surfaces. One attempted solution to this problemis shown in US. Pat. No. 3,098,604 issued to C. A. Dubberley for a Hermetic Refrigerant Compressor. As shown therein,

a centrifugal pumping means is employed to'cause the oil to flow upwardly to the bearing surfaces from the collecting sump. The oiland refrigerant are centrifuged by the rotary action of the rotor shaft so that the oil flows radially outwardly through a port at the upper 30 end of the delivery passage into the main bearing oil groove and the lighter refrigerant is forced inwardly through the shaft to the axis thereof and thence, outwardly to a refrigerant receiving passage opening into and means for causing separation of refrigerant gas from the lubricating oil and delivering of the separated gas to the inlet for flow through the axial passage to the outlet, the improvement comprising means for conducting refrigerant gas, separating from the oil in the oil passage means intermediate the inlet and the outlet, to the axial passage intermediate the inlet and the outlet for flow to the outlet with the refrigerant gas separated from the lubricating oil and delivered to the axial l0 passage inlet.

The gas-conducting means may comprise a plurality of flow passages communicating with the axial passage at axially spaced positions.

The bearing means may comprise different diameter bearings with a gas vent passage in the shaft communieating with the bearings at the juncture between the different diameter portions.

BRIEF DESCRIPTION THE DRAWING tion means embodying the invention;

the upper refrigerant vapor-sealed portion of the casing. In one embodiment, Dubberley shows the provision of a vapor relief vent at the top of the oil groove communicating with the primary refrigerant vapor relief passage.

Inthe'May 1966'ASHRAE Journal, a centrifugal oil pump is disclosed at pages 72-73 having a similar arrangement wherein refrigerant gas is centrifuged out and-delivered to a receiving chamber at the lower end of the oilflow passage to'the bearings. In FIG. 3 of said publication, at second vent is provided at the top ofthe oil flow passage.

SUMMARY OF THE INVENTION The present invention comprehends an improved rotary compressor structure provided with means for removing vaporized gas from the lubricating oil from one or more intermediate portions of the bearing, i.e., between the inlet and outlet of the oil lubricating passage thereto. Thus, the present invention comprehends an improved lubricating means in such a rotary compressor wherein vaporized gas is removed from the lubricating oil substantially at the portion of the system wherein it is generated to provide an improved gas lock-free lubrication of the compressor bearings.

More specifically, the present invention comprehends the provision in such a rotary compressor having a rotor rotatably journalled in a bearing means,oil passage means for conducting lubricating oil from an inlet, between the rotor and bearing means, and to an outlet, means for causing flow of the lubricating oil through said oil passage means, an axial passage in the rotor for conducting refrigerant gas from the inlet to the outlet,

FIG. 2 is a'fragmentary horizontal section thereof taken substantially along the line 2--2 of FIG. 1; and

FIG. 3 is a schematic view of the refrigeration system.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the exemplary embodiment of the invention as shown in the drawing, a compressor generally designated 10 is shown to comprise a rotary compressor having a rotor 11 including a drive shaft 12 driven by an I pressed refrigerant gas is delivered through adischarge tube 16 to a precooler 17andreturned to the housing 14 through a return tube 18, The high pressure gas is then delivered through a discharge tube' 19 to a series connection of a condenser 20, a flow restricting capillary 21, and an evaporator 22 wherein the compressed refrigerant vapor expands to effect the desired cooling operation. The expanded refrigerant is then delivered back to the compressor through a return tube 23 to be recompressed by the rotor 11.

Housing 14 defines a lower sump portion 24 wherein lubricating oil 25 is collected for circulation to the compressor bearings. The oil is delivered upwardly from the sump 24 through an oil conduit means 26 extending upwardly through the rear head 27 of the compressor. The rotor is provided with a pair of vertical oil passages 28 opening at their lower ends into the lower face 29 of the rotor confronting the upper face 30 of the rear head. At the upper end, the passages 28 open through the upper face 31 of the rotor to an annular groove 32 therein. Shaft 12 is provided with an axial bore 33 which extends through the rotor to open at its lower end through the lower face 29 in communication with the upper end of the oil conduit 26.

Shaft 12 includes a large diameter lower end portion 34 and a smaller diameter upper portion 35 connected by a frustoconicalconnecting portion 36. A suitable annular bearing 37 is provided in a large diameter lower recess 38 of the front head 39 for rotatably journalling the shaft portion 34. A spiral oil groove 40 is provided on the outer surface of shaft portion 34 for conducting the lubricating oil to the inner surface of the bearing 37. At its upper end, the oil groove 40 opens into an annular chamber 41 extending about the connecting portion 36 of the shaft and opening at its upper end to the space 42 between the upper shaft portion 35 and an upper tubular extension 43 of the front head. The upper shaft portion 35 further defines an outwardly opening annular groove 44 adjacent shaft connecting portion 36 and a motor journal oil groove 45 is provided in the outer surface of shaft portion 35 extending upwardly from groove 44 to an annular space 46 in the motor armature 47 above the upper end of the bearing extension 43. Shaft portion 35 is provided with radial passages 48 communicating between v the upper end of the axial bore 33 and annular space 46. Clearance 49 is provided between armature 47 and the radially outer surface of the bearing extension 43 opening downwardly from annular space 46 to the head pressure space 50 within housing 14. v I

. As shown in FIG. 2, the rotor 11 is provided with a blade 51 received in the pumping chamber 52 of a cylinder 53 to define the high pressure pump means of the compressor. The centrifugal forces generated on the lubricating oil by the rotation of the blade 51 in the chamber52 as the oil is delivered thereto effectively circulates the oil upwardly from the sump 24. More specifically, rotor 11 defines a downwardly opening plenum chamber 54 at the upper end of the oil delivery conduit 26. When the compressor is running, oil is delivered by gravity. to the plenum 54 and is forced therefrom to the oil passages 28 by the centrifugal forces generated by the opening rotor 11 and blade 51. The oil is forced upwardly through passages 28 into the an nular groove 32. The oil is conducted upwardly therefrom by the oil grooves 40 for lubricating the bearing 37 and for delivering oil upwardly to the motor bearing grooves 45 for lubricating the upper bearing portion 43. The oil overflows the upper end of grooves 45 into annular space 46 and thence downwardly through clearance 49 to return to the sump 24 for recirculation.

As indicated above, some refrigerant fluid becomes dissolved in the oil and is carried therewith upwardly through tube 26. However, as the oil is heavier than the refrigerant fluid, the centrifuging action that takes place in the plenum chamber 54 causes the lubricating oil to flow radially to vertical passages 28 then axially to annular groove 32 and then radially outwardly through annular groove 32 to the bearing 37 while refrigerant fluid is forced inwardly to axial bore 33. The rotor is provided with radial passages 55 extending between groove 32 and axial bore 33 and any additional refrigerant fluid centrifuged from the lubricating oil in passages 28 is forced radially inwardly from the annular groove 32 to the axial bore 33.

The oil, in moving upwardly through bearing 37, tends to be heated by the relatively hot bearing surface and further refrigerant fluid may be vaporized therein to be received in chamber 41. Shaft 12 is provided with radial passages 56 communicating between chamber 41 and axial bore 33 for conducting the vaporized refrigerant from chamber 41 also into the axial bore 33.

Thus, the lubricating oil delivered to the upper bearing 43 by the oil passages 45 is relatively free of vaporized refrigerant fluid thereby assuring that the entire bearing means of the rotor shaft is efficiently lubricated with gas-lock thereof by the refrigerant vapor being effectively precluded. The radial passages 48 at the upper end of the axial bore 33 serve as centrifugal gas pumps forcing the refrigerant vapor radially outwardly from the bore 33 to flow downwardly through clearance 49 into the head space of the housing 14. This centrifugal pumping action maintains the axial bore 33 and the radial passages and 56 under a suction pressure tending to facilitate the withdrawal of the vaporized refrigerant fluid at all times during the operation of the compressor thereby further effectively assuring gasfree lubrication of the compressor bearings.

To illustrate the flow of the oil herein, small circles have been indicated in the flow path through the bearing means upwardly from the sump.

As illustrated in FIG. 2, refrigerant gas may also flow to the center passage 33 through the blade slot 57 in the rotor in which the blade 51 is slidably carried.

Thus, the present invention comprehends an improved lubrication system for a rotary compressor wherein refrigerant fluid dissolved in the lubricating oil is separated therefrom and caused to follow a separate flow path from the flow path of the lubricating oilin lubricating the compressor bearings. The rotary motion of a number ofcompressor portions is utilized to effect centrifugal separation and forced flow of the vaporized refrigerant to effectively preclude gas lock? in the compressor bearings and provide improved gall-free operation. The lubrication system is extremely simple and economical of construction while yet providing the improved lubrication function.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

I claim:

1. In a rotary compressor having a rotor including a shaft rotatably journalled in a bearing means, oil passage means for conducting lubricating oil which may have refrigerant gas therein from an inlet to between the rotor shaft and bearing means and therefrom to an outlet means for causing flow of the'lubricating oil through said oil passage means, an axial passage in said rotor for conducting refrigerant gas from said inlet to said outlet, and means for causing separation of refrigerant gas from the lubricating oil and delivering of said separated gas to said inlet for flow through said axial passage to said outlet, the improvement comprising means for conducting refrigerant gas, separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet for flow to said outlet with the refrigerant gas separated from the lubricating oil and delivered to said axial passage inlet.

2. The rotary compressor means of claim 1 wherein said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet comprises a plurality of flow passages communicating with said axial passage at axially spaced positions.

3. The rotary compressor means of claim 1 wherein said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet comprises passage means extending radially through said rotor.

4. The rotary compressor means of claim 1 wherein said rotor includes a shaft portion journalled in said bearing means and said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet, comprises passage means extending radially through said rotor shaft portion.

5. The rotary compressor means of claim 1 wherein said rotor includes a first shaft portion adjacent said outlet and a second shaft portion having a diameter larger than the diameter of said first shaft portion and extending axially away from said first shaft portion toward said inlet, said shaft portions being journalled in said bearing means and said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet comprises passage means extending radially through said rotor including a first passage extending through said rotor at the juncture of said first and second shaft portions and a second passage extending through said rotor at the end of said second shaft portion remote from said first shaft portion.

6. The rotary compressor means of claim 1 wherein said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet includes an annular groove in said rotor opening radially outwardly toward said bearing means and a passage in said rotor communicating between said groove and said axial passage.

7. In a rotary apparatus having a rotor rotatably journalled in a bearing means, oil passage means for conducting lubricating oil from an inlet, between the rotor and bearing means, and to an outlet, means for causing flow of the lubricating oil through said oil passage means, means defining a gas flow passage for conducting gas from said inlet to said outlet, and means for causing separation of vaporizable gas from the lubricating oil and delivery of said separated gas to said inlet for flow through said gas flow passage to said outlet, the improvement comprising means for conducting additional gas, separating from the oil in said oil passage means intermediate said inlet and said outlet, to said gas flow passage intermediate said inlet and said outlet for flow to said outlet with the gas previously separated from the lubricating oil and delivered to the gas flow passage inlet.

8. The rotary apparatus of claim 7 wherein said gas flow passage extends longitudinally through said rotor.

9. The rotary apparatus of claim 7 wherein said additional gas is caused to separate from the lubricating oil in said oil passage as an incident of heating of the lubricating oil therein.

10. The rotary apparatus of claim 7 wherein said outlet includes. passage means for conducting the separated lubricating oil and gas together to a discharge 

1. In a rotary compressor having a rotor including a shaft rotatably journalled in a bearing means, oil passage means for conducting lubricating oil which may have refrigerant gas therein from an inlet to between the rotor shaft and bearing means and therefrom to an outlet means for causing flow of the lubricating oil through said oil passage means, an axial passage in said rotor for conducting refrigerant gas from said inlet to said outlet, and means for causing separation of refrigerant gas from the lubricating oil and delivering of said separated gas to said inlet for flow through said axial passage to said outlet, the improvement comprising means for conducting refrigerant gas, separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet for flow to said outlet with the refrigerant gas separated from the lubricating oil and delivered to said axial passage inlet.
 2. The rotary compressor means of claim 1 wherein said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet comprises a plurality of flow passages communicating with said axial passage at axially spaced positions.
 3. The rotary compressor means of claim 1 wherein said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet comprises passage means extending radially through said rotor.
 4. The rotary compressor means of claim 1 wherein said rotor includes a shaft portion journalled in said bearing means and said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet, comprises passage means extending radially through said rotor shaft portion.
 5. The rotary compressor means of claim 1 wherein said rotor includes a first shaft portion adjacent said outlet and a second shaft portion having a diameter larger than the diameter of said first shaft portion and extending axially away from said first shaft portion toward said inlet, said shaft portions being journalled in said bearing means and said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet comprises passage means extending radially through said rotor including a first passage extending through said rotor at the juncture of said first and second shaft portions and a second passage extending through said rotor at the end of said second shaft portion remote from said first shaft portion.
 6. The rotary compressor means of Claim 1 wherein said means for conducting refrigerant gas separating from the oil in said oil passage means intermediate said inlet and said outlet, to said axial passage intermediate said inlet and said outlet includes an annular groove in said rotor opening radially outwardly toward said bearing means and a passage in said rotor communicating between said groove and said axial passage.
 7. In a rotary apparatus having a rotor rotatably journalled in a bearing means, oil passage means for conducting lubricating oil from an inlet, between the rotor and bearing means, and to an outlet, means for causing flow of the lubricating oil through said oil passage means, means defining a gas flow passage for conducting gas from said inlet to said outlet, and means for causing separation of vaporizable gas from the lubricating oil and delivery of said separated gas to said inlet for flow through said gas flow passage to said outlet, the improvement comprising means for conducting additional gas, separating from the oil in said oil passage means intermediate said inlet and said outlet, to said gas flow passage intermediate said inlet and said outlet for flow to said outlet with the gas previously separated from the lubricating oil and delivered to the gas flow passage inlet.
 8. The rotary apparatus of claim 7 wherein said gas flow passage extends longitudinally through said rotor.
 9. The rotary apparatus of claim 7 wherein said additional gas is caused to separate from the lubricating oil in said oil passage as an incident of heating of the lubricating oil therein.
 10. The rotary apparatus of claim 7 wherein said outlet includes passage means for conducting the separated lubricating oil and gas together to a discharge space. 